Simoloyer® FAQ - Zoz GmbH

General Questions about Simoloyer^®

What is Simoloyer^® – Full Maltoz^® System?
This is the base, ready to use for batch-processing. Depending on application there are several possibilities.
The Full Maltoz^® System (FMS) contents the air-lock system for processing under controlled atmosphere (inert-gas). Processing under vacuum is also possible.

Component parts of the FMS are:
The Simoloyer^® incl. grinding-unit (standard type) and PC,
drain-gratings (3 types for discharging under air as well as under protected atmosphere),
equipment parts for as cross-pieces, adapters, vacuum-/gas-connection, containers, side-adapter,
sample- and leakage-tubes
grinding-media (standard), clamps / center-rings / blind-lids and tool-kit, documentation.

Using the “Full Maltoz^® system” the Simoloyer^® is able to be used with all its features for high kinetic processing under inert-gas and/or vacuum in batch mode directly (after connection to power-, water- and gas-supply of course).

What is HKP, HEM, FMS, CMB, SOP, PCA (usually used shortcuts)?
HKP    High Kinetic Processing
HEM    High Energy Milling (historical for HKP)
FMS     Full Maltoz^® System
CMB    Critical Milling Behavior
SOP     Simoloyer^® Operation Program (Maltoz^®)
PCA     Process Control Agent

Can I take samples?

Yes, there are sample-tubes with a volume of 10ml part of the delivery volume. Sample can be take under air, vacuum and inert-gas during a handling break (Maltoz^®).

Is up-scaling of the system itself and from other laboratory systems possible?
Usually yes – to be continued… (from CM01 – from PBM / SPEX…RM, TRM)

Is particle size reduction possible?
Yes… (PCA, wet/dry…, comments on agglomerates…)

Simoloyer^® – is wet and dry milling possible?
Yes. Even if the system is originally built for dry processing (air, inert-gas, vacuum), wet processing is also possible. The compatibility of materials should be checked in any case, for details please ask Zoz GmbH or one of its authorized agents.

Is cryo-milling possible?

For processing at low temperatures the TTB-configuration is available (CM01-CM20). Here the cooling-jacket of the grinding-unit is used for it cooling down by means of a glycol-mixture up to -30°C. Due to HKP (High Kinetic Processing) a lot of heat is produced within very short processing time. For keeping the system as cool as possible a suitable cycle-operation can be used, which may content cooling sequences.
The system is not built for processing under lower temperatures e. g. using dry-ice, liquid air/nitrogen or similar, since it is built for vacuum application. The grinding-unit is not pressure-tight, which would be necessary in case of processing under very low temperatures. In this case the grinding-unit should be operated in open condition what we would like to avoid (gas-/powder exhalation).

What is the standard configuration of the Simoloyer^® Technology – and what else is available?
Beside the “Simoloyer^® CM01 – Full Maltoz^® System”, which is a table top equipment and which is able to be used directly after connection to power, water and gas supply, there are some more options and features possible.
Examples are the sound-adsorption cabinet, configurations, other types of grinding-units or the vacuum-pump system, which is strongly recommended in case of processing under inert-gas for preceding evacuation of the system before processing.
Very often installation is done on-site, even if training is recommended either here in the company or at the customer of course. So the set-up training is an option.

Return to top

Simoloyer^® – some details, configurations, types

What is Simoloyer^® CMxx-ABxx (auto-batch-unit ABxx)
One option is the ABxx, which is connected with the CMxx where some parts of the equipment of the “Full Maltoz System” are used. A grinding-unit Wxx-xxlm-s2 is necessary, which is able to be ordered additionally or initially (in this case the standard grinding unit Wxx-xxlm of the “Full Maltoz System” is upgraded to the Wxx-xxlm-s2).

What is Simoloyer^® CMxx-s1 (semi-continuous)
This is a further option, based on the “Full Maltoz System again. Here another grinding-unit W20-20lm-s1 is required. It is required and strongly recommended, that the “Full Maltoz System” is present as well for first tests and other applications.

What is the TGD-unit?
The TGD08-20 (option) is designed for improved discharging. In some cases it is strongly recommended reducing the discharging time and rotational speed of the rotor during discharging operation. Therefore a carrier-gas assisted system is connected. The stream transports the powder into a closed circuit. The gas (air or inert-gas) is driven by a stronger pump (side channel turbine), the powder and gas is separated by a cyclone.

What configuration / options / features are available?
The Full Maltoz^® System is ready to use (operate), after it is connected to power, water and often inert-gas. It is prepared for batch-process of powder materials including the base-unit, a standard grinding-unit and component parts for processing under protected atmosphere.

Depending on application there are further possibilities:
Vacuum-pump-system: We offer such a complete system if it is required and if a suitable system is not available on-site. This is for processing under controlled atmosphere. The gas (air) inside the grinding-unit, air-lock and containers is “kicked out” by evacuation before re-filling with inert-gas. Processing under vacuum is also possible, but is done in exceptional cases only (there should be reasons for, e. g. powder-material for vacuum-application).

TGD: This feature is for improved discharging procedures. By this powder is discharged in shorter time by using lower kinetic (rpm of rotor); discharging should be as smooth as possible for avoiding further high-medium-low-processing.

AB20a: This goes into direction of industrial application, since the system is automated charged and discharged. Powder preparation is done before connecting the feeder-containers to the system. This is really Auto(mated)-Batch. It includes most of the feature of the TGD.

HTB/TTB-configurations: These are special features. Standard-grinding units are able to be modified for lower or higher process-temperature processing. This is mainly in case and in the field of mechano-chemistry.

What is HTB-configuration?
… up to 200°C, without cooling-jacket of vessel

Is it possible to heat up the system (grinding-unit)?
The standard grinding unit is normally cooled by usually water. But the new design allows not cooling the vessel itself (for cooling the bearing/sealing-unit there is a second cooling circuit). In this way, the vessel is heated up by processing. But because the temperatures are not allowed to exceed approx. 90°C and because it is probably difficult for reproducibility there are other possibilities. The one is the HTB-configuration. Here the cooling circuit is used for heating up the system up to 150°C by using hot fluid, which is heated up by an external heating/cooling-system.
The other system is the heatable grinding unit W01-2lh. There a temperature of 200°C can be reached by electrical heating elements. The cooling circuit of the vessel doesn’t exist here.
For handling the HTB-configuration is a bit easier, also a standard grinding unit can prepared for it, but the max. temperature is not as high as at the –lh-system.

How can we connect the component according to the attachment “Equipment CMxx”?
To connect component there are surveys / descriptions available. Some examples which component part is able to be connected in which situation are mentioned there. Please ask the Zoz GmbH or one of its authorized Sales-Partners.

Return to top

Maltoz^®

What is Maltoz^®?
Maltoz^® is the SOP for the Simoloyer system, which is developed at Zoz GmbH. By this software the Simoloyer is controlled with processing time and speed, furthermore several data is collected in a separate log-file (record of parameters).

Do we supply the CPU and what does it actually control? (Maltoz)
As part of the delivery-volume a PC will be delivered, which is necessary to operate the Simoloyer^®-systems by the Maltoz^®-Software (Maltoz^®-SOP).
The TGD is used manually via a control cabinet.
Furthermore Maltoz^® records some process parameters as time, rpm of the rotor, temperatures, power. The data are stored in a separate file which can be charted by e. g. MS-Excel.

Return to top

Air-lock/inert-gas/vacuum

What is air-lock?

The “air-lock” means a kind of interface between air and inert-gas/vacuum. It is possible to evacuate the grinding unit as well as the powder containers. Charging and discharging the powder material under inert-gas/vacuum is possible. So the “air is locked out”.
The DN40 (CM01) describes the size of the air-lock. Standard vacuum connections res. sizes are used (ISO). If a vacuum pump or system is available in your facility you may have a look on the connections which here consists of the DN40-desing, an inner or outer centre-ring and a corresponding clamp. For the Simoloyer up to CM20 sizes of DN16, DN25, DN40 and DN50 are used.

Is processing under controlled atmosphere possible?
Yes, this is possible; the documentation should give a hint on it. This is one of the main features of the Simoloyer^® system! It is possible to process under controlled atmosphere e. g. inert-gas or vacuum. For processing under inert-gas, the grinding-unit is evacuated first before it is refilled with inert-gas (e. g. Argon) again. For charging / discharging of powder material the air-lock system is used. By this the grinding-unit is able to be kept closed under inert-gas, containers and the air-lock itself is able to be connected and evacuated / refilled with inert-gas. By this the complete powder processing route is able to be done under controlled atmosphere. For charging the powder containers (valve-containers) are able to be “inertisied” in a Glove-Box or using the air-lock equipment. For dis-charging the containers are usually inertisied before the discharging-process using the air-lock system. For processing under vacuum a similar way is used using the air-lock system.

Is it possible to connect inert-gas (DN16) and vacuum (DN25) at the same time to achieve a vacuum and protective atmosphere?
Inert-gas connection is DN16 (flange-size) and vacuum connection is DN25. These connections are used, right. The flanges for connecting inert-gas and vacuum are at the calming-pipe, a part of the air-lock. The calming-pipe is a kind of cross piece (appropriate for powder processing) which is built for connecting inert-gas and vacuum. Of course, usually the system first is evacuated using the connection DN25, then the system is refilled with inert-gas using the connection DN16. Since the calming pipe is connected at the drain-grating As-G* or Ask (assembled at the grinding-unit) the vacuum / inert-gas is achieved inside the grinding-unit (if open ball valve(s)). Or – if the grinding-unit is closed – possible connected component parts like ball-valve-containers or sample-tubes can be evacuated/refilled as well on the other side of the calming pipe. It is the principle that the grinding-unit is gas-tight (if closed).

For CM20, the connected air-lock system can be DN40 or DN50, what is the difference between DN40 and DN50?
The air-lock system for the Simoloyer^® CM20 system is DN50. The DN** sizes are standard flange sizes for vacuum applications, DN40 is a bit smaller and used for the air-lock of the lab scale Simoloyer^® CM01.

What is the difference between W20-20l-RR (standard) and W20-20l-sam-RR in Grinding Units? Which one will be better in Mechanical Alloying (MA)?
E. g. for processing of ODS-powder material the standard grinding-unit (W20-20lm, charging and dis-charging using port P01a) or the standard grinding-unit with a second main-port (W2020lm-s2) is recommended. The second main-port (P01b) has the advantage, that this port is able to be used for charging, the standard main-port (P01a) for dis-charging. For ODS production we usually use the grinding-unit W20-20lm-s2. The type W20-20lm-sam is a very special one (separate cooling system) and not built any longer, since the cooling system and efficiency of the today’s standards is usually sufficient. The appendix “RR” is not used any longer; we should check our data-sheet.

Where to connect the vacuum pump?
Answer will follow (air-lock, side-adapter)

How is processing under protected atmosphere possible, what is air-lock?
The method for processing under protective atmosphere is using an air-lock. Maybe it is a bit like a submarine.
In principle, the vessel (grinding-unit) is able to be evacuated a well as the air-lock and e. g. containers which are connected there. The grinding-unit itself and the equipment is vacuum-tight.
By this, it is possible to charge powder material under vacuum (normally not necessary or difficult) or inert-gas (e. g. using a glove-box), to process the powder and to discharge the powder under such conditions. Charging under air is also possible of course.
Sometimes people ask us whether it is possible to put the grinding-unit into a Glove-Box where an air-lock needs to be passed; but this makes no sense (and is not possible) since the grinding–unit itself is a kind of Glove-Box already. The powder is discharged by processing (using the Maltoz^®-software) and collected in ball-valve containers for further handling.
For charging, the main-port of the grinding-unit is in position “on-top”; that means the powder falls down by gravity. For discharging the main-port is turned by 180° and by operating with low kinetic the powder falls down into a valve-container. A special drain-grating prevents that powder only, not the grinding-media moves out of the vessel.
Depending on application and powder material there are usually three different drain-gratings delivered, which combines drain-gratings with the lock (gas-, powder-tightness) and which are part of the air-lock of the Simoloyer^® system.

Return to top

Simoloyer^® – peripheral devices

The sound dampening chamber (sound-box), how are the lights and power connections configure inside the box, as well as how does the external power and water required for the mill feed through the box?
The sound-box (sound adsorption cabinet) will be prepared so that outside the power- and water-supply is to be connected on-site at separate connection-boxes. Inside the box water and power is prepared and pre-installed for the Simoloyer system and its equipment.
Furthermore it is arranged that there will be installed fluorescent lamps on the ceiling inside the box as well as some sockets on the wall (inside the box) for PC, Vacuum-Pump etc.

Return to top

Technical questions to Simoloyer^®

What is the noise of the system?
High Kinetic Processing, and all other milling processes, produces a lot of noise (up to 95dB(A)). So the system either are used in special “milling-rooms” or suitable sound adsorption cabinets, e. g. the SB01 or SB08-20, are used.

What is the maximum load of the unit?
Depending on material and applications – this is not as easy / fast to answer. Please let us know some more details.

Which size of Grinding Unit for Simoloyer^® CM01?
For materials with a density of 2-5g/cm3 and a powder charge of 200g/batch we recommend a Grinding Unit W01-2lm.

How to change rotor / pre-seal
To be answered separately upon inquiry.

What are the wear parts of the system?
Answer will follow (rotor, grinding-media, vessel (?), pre-seal, spare-part kit, valves…)

What about corrosion resistance of the system?
The main parts of the grinding unit as well as all component parts are mainly made by stain-less steel. In case of interest and further information, please let us know.

What power supply is needed?
The Simoloyer^® systems are prepared for power-supply used in EU. In case of alternative power supply either a transformer or electrical components (e. g. frequency converter) is able to be delivered. Please ask the Zoz GmbH or one of its authorized Sales-Partners.

What external sizes and power is needed?
We are able to supply corresponding information, where power and space requirements are given.

Are dimension sheets of the Simoloyer^® systems available?
Yes, upon inquiry. Please let us know some more details about your project.

Which kind of grinding-media is possible?
Standard: 100Cr6, also possible e. g. special stainless steel, ZrO₂, Si₃N₄, THM, but not e. g. Al₂O₃. Further information is available upon inquiry.

What is the life time?
For the base unit we do not have a number, it depends on processing time, applications and care. I do not remember that we had to change it completely; it seems a very stable system. The life-time of the grinding-unit itself depends on the application and its type. The bearing flange of the grinding unit (drive shaft, seals) needs to be checked in time.
In case of the grinding unit THM the lining has to be checked in time as well. This also concerns the equipment. E.g. the ball valves and seals also need to be checked in respect to its tightness in time.

What materials are used (grinding-unit, grinding-media)?
The standard grinding-unit if the Simoloyer is made mainly by stainless steel (1.4301 / AISI 304). This covers the vessel and the rotor-blades. The tips of the rotor-blades is made by welded Co-based hardphase material (mainly Co-Cr-W-alloy).
As grinding-media we usually use balls Ø5mm made by 100Cr6 (Fe with 1,5%Cr).
This configuration should be used if possible and useful. Please find enclosed some information about comparisons of various milling devices, where contamination is a topic. One feature of the performance of the Simoloyer^®-technology is the low contamination due to the principle of collision (not only shear & friction).

There are further options:
As grinding-media we also often use balls Ø5mm made by ZrO₂. By this the contamination from the steel-balls is able to reduced.
In some cases we also use a grinding-unit SiN, where the inner shape is lined with and the rotor blades are made by Si₃N₄. Here also grinding-media ZrO₂ is used
In case of need, applications and if possible, there are more possibilities in choosing materials for the HKP-tools.

Does this system have any components made of glass?
Yes. There are component parts made of glass. There assembled a leakage-tube (glass) assembled next to the grinding-unit. Furthermore for sampling and discharging there are often used a
sample-tube (glass) and glass-flange container.

Return to top

Set-up / training / delivery conditions

Is set-up / processing in a “clean-room” possible?
As maybe known, the Simoloyer^® is vacuum tight! During processing there is no dust available. Of course during handling dust may be present, so suitable vacuum-cleaners are able to be used.

Is training possible?
Yes, of course. Training can be done on-site (at the customer) or at Zoz GmbH. It usually takes 2 days approximately.

What are the delivery conditions?
Answer will follow.

Are the quotes with or without VAT?
The quotes are usually without VAT.

What is the delivery time of the systems?
A standard Simoloyer^® CM01 is usually in stock (1-2 weeks), CM08 and CM20 maybe in stock as well, if not, the system can be delivered in approx. 3-4 months. The THM-version needs usually 4-6 months.

Return to top

Handling

How to discharge powder material? (handling)
Using drain-gratings, turning the grinding unit by 180° (main-port shows downwards), discharging process by Maltoz^®.

Return to top

Processing

What is the batch-size, processing-time, yearly/monthly/daily production?
Answer will follow, it is all related together.

Is the system suitable for my application?
Depends on application – please let us know details – maybe it can be find out in our lab.

What process temperature can be reached, what is the process-temperature?
Answer will follow (If the process temperature reaches a value of 80°C, the system will stop automatically. This is the reason that the process temperature cable must be connected at the grinding-unit (vessel).)

Which temperatures / pressure is present?
Answer will follow (which temperature?; pressure-measurement possible, also vacuum-pressure-measurement…)

Which atmospheres are possible?
Answer will follow (depending on application, air, Ar, Ar/H2, CO2, (H₂), He… )

Return to top

Collection of further questions

Simoloyer in a Glove-Box? (in general)
Possible, but is this really necessary? Since the grinding-unit and its component parts are vacuum-tight, handling with powder material is directly done at the system. Handling of powder containers (charging / dis-charging) can be done in the Glove-Box. The powder containers including the sample tubes fits to the air-lock system (flange sizes ISO-KF).

What is vacuum-pump system and what it is for? (configurations / in general)
See above (air-lock / processing under protected atmosphere).

What about contamination? (in general)
In general, the rotor is the main wear part since low surface in work and lots of collision. The grinding-media causes probably the main amount of contamination due to its high amount of surface in action. A very small amount of contamination or almost no wear and tear is caused at the grinding-vessel itself.

Glass-vessel? (configurations)
This vessel is only for demonstration. A grinding unit consists of a bearing flange and vessel. For having a look inside it is possible to assemble the glass-vessel at the bearing flange.
It should be noted here, that “glass” means Plexiglass which has a short life time. Glass itself will not survive due to the impacts of the grinding media (balls).

Where is the cooling connection we will be need for the compressor? (technical / cooling)
The Simoloyer^® is equipped with a cooling block, where standard cooling water supply is connected. In this case the standard cooling water is connected with the sound-box, which is connected onside outside the box.
The heating- and cooling-unit is directly connected with the grinding-unit (cooling circuit of the vessel).
An air-compressor is not required / not allowed. Inert-gas is also connected and supplied on-site outside the box; inside it is prepared for the supply of inert-gas to the grinding-unit.

Are we getting this option: extended Simoloyer^® cooling block for heat exchanger? (technical / cooling)
Either a standard cooling-water supply on-site is used or the cooling-unit for TTB-configuration can be connected to the cooling block (standard for Simoloyer^®-systems) for standard-processing.

How much material THM? (processing)
This depends on the material itself and the size of the Simoloyer^®. Hard-metal has a relatively high weight so we can neglect the volume almost. We would start for the pilot test with 800g-1000g using the CM08 and 2-3kg using the CM20.

What is the processing time? (processing)
It depends on the application and the material. The processing time should be hold as short as possible due to wear and tear on the rotor, grinding media and vessel.

What consumables / spare-parts do I need? (technical)
It is recommended to quote some spare parts as well; at least we can quote an additional rotor.

What is the nominal power and what about running costs Simoloyer^® CM20? (technical)
There probably are several operational supplements, power and cooling-water is one of them, other are e.g. inert-gas, spare-parts etc.
The nominal power of a CM20 is max. 22kW. Depending on the application the system does not need this maximum value.
The amount of water is max. 30l/min; we use it mainly with approx. 15l/min.; normally the company’s internal water circuit is used.

Return to top

Unsorted

Is rework / overworking / reconditioning of rotors possible?
In case of checking / exchanging in time: yes.

From development to industrial applications – how?
First stage – development / first production / batch-mode:
Charging via 2^nd main-port using charging valve Bsk (free pass) in charging position.
Discharging via (1st) main-port using drain-grating (Ask/As-G1½) in discharging position (main-port down).

Second stage – TGD (“half-automated”):
Charging via main-port using charging valve Bsk (free pass).
Discharging via 2nd main-port using drain-grating (Ask) and TGD.

The difference in arrangement is only, that the main-ports are changed in its function; the parts (drain-gratings, charging valve) are the same. In combination with the TGD it is recommended using the 2nd main-port for powder flow and connection to the TGD, it more suitable connecting it at the side.
The powder is charged manually, but discharged by means of the TGD. The grinding-unit does not need to be turned into discharging position.

Third stage – AB20a (“Auto-Batch”):
Charging and discharging is automated (powder, powder mixture needs to be prepared of course before connecting to the unit).

Return to top

Some detailed questions and answers:

The raw material size is 50um-10um. During the material preparation, the valve container needs to be vacuumed. How to avoid the powder being sucking out with the air?
Evacuation is done slowly (low flow-rate), refilling can be a bit faster; the pressure-situation inside the container is checked by manometer.

Some agent needs to be added during the processing to avoid the material getting sticky together. During the trial, if the material has already been sticked together inside the chamber, how to get the sticky parts out?
Normally PCA (process control agent) is added to the raw material before inertisation the charging containers. For some cases a sample port or additional Auto-Batch port can be prepared for intermediate addition of PCA. For manual batch use an intermediate adding of PCA is done manually as well using the air-lock system.
In any case: sticking has to be avoided during processing. A slight crust may appear, but it should not grow always. Either PCA or maybe cycle operation may help to avoid growing crusts.

Automatic Discharging: What is the material discharging rate? Can the powder be discharged completely 100%?
It should, for stable processing it has to; otherwise there is a high expense in cleaning and removing the grinding-unit all the time. So the processing rate should be around 100% (sometimes e. g. 98, sometimes 102%).

Discharging mesh size: The mesh size is 3mm. During the processing, some balls can be broken. The broken ball may be discharged mistakenly with the powder. How to avoid this?
Broken balls should be avoided; a higher quality of suitable material has to be used. In any case it is recommended to sieve the material (e. g. after passivation, since the filter need to be cleaned in time as well) to be on the safe side. If the material is not magnetic a magnetic filter can be arranged somewhere (after / during discharging)

How to control temperature of the grinding unit? How to monitor the temperature inside the chamber? What is the normal temperature inside the chamber during material processing?

It is measured the process temperature and shown on the Maltoz^®-screen. We are working on further metering points at grinding-units at the moment, since it is not as easy to measure the inside temperature during processing due to grinding-media and powder.
The temperature depends on the processing parameters and powder materials. Furthermore there are cooling sequences possible or lower rpm used during cycle operation. So it is usually 30-150°C.

Speed of the grinding unit: to machine the same material on different machines, such as CM02, CM20, CM100 and CM400, is the speed of the machine RPM different?
Yes since the rotor diameter is different. But the tangential speed of the outer side of the rotor-blade keeps constant, we call this speed MRV (Maximum Relative Velocity). We look also on the relative velocity (velocity-difference between fast and slow balls).
Comment: It is CM01 (- unfortunately, CM02 would be right but is not used, the number of CMxx is normally according to the standard size of grinding-unit, like CM100).

How long will take to discharge the material if AB100a is used for CM100 machine?
Normally 5-10min. It should as fast as possible, but not all within 1 second (since the cyclone and pipe-tube-system need to handle the amounts of powder).

Is the grinding unit (CM100 machine upwards) driven by two motors on both end?
No, the new generation has one single drive (as CM01, CM08, CM20). An actual product information is available.

The life time of the key components or spare parts.
The main wear parts are rotor and grinding-media with lifetimes of 500-1500 hrs, maybe more, depending on material & process parameter. In this case there is ductile-soft Al with hard B4C used. PCA also has an influence.

Is wet-processing using CM-Simoloyer^® possible?
Yes.
As mentioned already, wet-processing is possible and allowed, but there is other equipment also on the market which might be suitable. But the applications are different. Wet-milling is normally e. g. for fine-grinding. So this is another world, not our usual application. We go other ways: dry-processing.
Wet-processing of nanostructured (example MKE) is not possible very often.
If we do, we only do it to show the performance of the CM-system or, since we do not have a real wet-mill (normally the slurry is pumped in the circle during wet-processing) we use it for wet-processing if necessary.
Wet processing is normally only used with the CM01-system, which is a lab-device which gives R&D-departments some more possibilities (they do not need an additional wet-mill).
Another example: solid state reactions – only dry-processing.
Our dry-mill (CMxx) is able to be used as wet-mill, but a wet-mill is not suitable for dry-processing!
So, wet-milling is not a big topic here since we are focussed in dry-processing for nanostructures, MA, RM etc. what is usually not possible with wet-processing – the principle of deformation-fracture-welding does not work by wet-processing!
It is also important to see, that liquids damps and reduces energy-transfer into the powder. You may fell that on the street during heavy rain: aquaplaning.
In this exceptional case (Al₂O₃ wet-processing for 10min) it was only intended, that I needed a bit sub-micron- or nano-Al₂O₃ for tests of nano-structured materials.
Since the energy is/was relatively high, there are some points to be observed. The Al₂O₃ got grey (Fe-contamination, if doing 2 times it probably will be a bit less grey). So the ceramic powder needs to be cleaned (e. g. chemical route). We also didn’t use ceramic grinding-media or ceramic grinding-unit (for reducing Fe-contamination). The amount of liquid is limited to approx. 0,1 x [volume of grinding-unit] (e. g. 200ml using grinding-unit W01-2lm), otherwise the liquid flows in the bearing-flange through the pre-seal-unit, what is not really recommended.
Also the amount was low (50g powder with 2500g grinding-media and approx. 100ml special alcohol). After this, the powder was dried. What we may do is testing the same, but without the liquid.
The idea was also to avoid agglomerations during dry-processing (not confirmed) and thinking in a currently running funded project.
It also makes us a bit more independent and gives some new ideas for the future – maybe.
So, please focus on dry-processing for the CM-Simoloyer^®, therefore the system is designed and built. But if required, wet-processing is possible and is a nice feature.
For information: please check the information brochures of the CM-Simoloyer^®, there is mentioned “wet- & dry-operation”!
Finally, a part of the cleaning-procedures is often done by wet-processing here
fillingratios

Temperatures, filling ratios and process parameter:

Depending on the application there are some process parameters possible. We here use the Simoloyer^® system mainly in the way not to exceed 40% of the filling-ratio. So the amount of grinding-media is often in the range of 2000-2500g (CM01 only), whereas, depending on the powder material, 100-250g (Powder to Ball ratio PBM of 1:10-1:20) is used.
By this there is free space for free movement which is recommended res. required for having this collision-effect and energy transfer into the powder material.
There are sometimes other modes possible e. g. simulating other kinds of grinding-equipment where the filling ratio is increased, but then the rpm is reduced since there are limits in energy transfer from the drive (the system cannot keep the rpm constant if the max. available power is reached).
On the other hand, no question, the Simoloyer^® technology is a “cooling-media heating-up equipment” in any case. A lot of energy also is transferred to the cooling media.
Since heating is much easier than cooling (cooling needs much more energy) the laboratory equipment the cooling circuit needs a chance to reduce its temperature. If using the thermostat a corresponding cycle operation can be programmed so that the cooling temperature is lowered.

Return to top

Cycle operation / discharging cycle

The discharging processing depends strongly on the powder material and its discharging behavior. It is recommended not to exceed the rpm which is used during operation.
The principle is:

rpm as low as possible
discharging time as short as possible

Since discharging is also a kind of processing the discharging time and speed should be decreased as possible. For testing we here have a look on the powder flow during discharging using a glass container by variation the rpm manually or by program (Maltoz^®-software).
Cycle operation indeed sometimes helps to improve the discharging procedure. The example you mentioned is the discharging cycle operation (CM01: 1300/900rpm) for a special application which was done successful. For processing the time and speed was vice-versa. It looks like that there are thermal or physical or mechanical or thermo-dynamical effects using a cycle operation and maybe a steady state of the powder characteristic is not stable (in comparison to constant rpm processing).
An alternative for reducing the discharging time and speed is using the TGD-unit, where the powder is picked-up by a gas-stream inside the grinding unit and separated outside by a cyclone. This process also can be done under inert-gas.

powderrests

Rests of powder (discharging)

This is also a question of the behavior of the powder material. This can be sticking, crust or at least cold-welding. All should be avoided if possible. We here check the output ratio, maybe there will remain a bit powder material inside the grinding-unit (5-10%) after the first or second batch, but after the third batch around 100% of the charged powder material should be discharged was well. For a lot of applications a bit remaining material does not have an influence to the product since the curst is often exchanged during processing.
This should be observed in any case!
If there is missing always powder material inside the grinding unit either an improved or extended operation- and discharging-process is to be checked or developed, or e.g. a suitable PCA (process control agent) might be taken into consideration.
Another hint is, depending on rpm and material, maybe it helps in some cases, that the grinding unit is turned during processing. E.g. if a processing time of 1h is planned, the idea is that after 20min processing time the grinding-unit is turned into discharging-position (main-port P01 down, but keeping the grinding unit closed, only turning the grinding-unit, nothing else), continuing the process and after further 20min the grinding unit is turned into the charging / operation position again (main-port on top) where the operation is continued for the last 20min (it is recommended to that the last processing step is done in this operation position – main port on top – to avoid a possible crust at the main-port itself).
Short description – as example: processing for 1h – position of main-port P01:
20min operation-position – 20min discharging position – 20min operation position
By this it may happen that the crust inside is removed or moved inside the vessel.

In other few cases, especially for temperature-sensitive materials like light metals, we use a modified cycle operation with a break indeed (0 or very low rpm for 1-2min), which helps to cool down powder and grinding-media.
millingcompare

Comparison of various milling devices

It is indeed an interesting topic to compare a Planetary Ball Mill (PBM) with a Simoloyer^®. We have one publication where we did that exactly (upon inquiry). A rough summary about the features of a Simoloyer^® system might be sent as well a. Maybe one of the main interesting points is that the Simoloyer^® is able to be scaled-up, what is not possible normally with the PBM.
Up to now we found that the Simoloyer^® is much faster or has a higher out-put ratio in comparison to other ball mills; sometimes it can do jobs where a PBM gets in problems (e. g. sticking effects, amount of process control agents, homogeneity, phase-formation); maybe there is also the way versa, but I never heard about.

Can we connect a pressure / temperature measurement device?
The pressure measurement is relatively easy by connecting a manometer at an auxiliary port, which is directly connected with the vessel. We also use such a port for measuring the vacuum pressure if necessary or required.

What temperatures are present during processing?
For temperature measurements we have to be careful. There are a lot of temperatures, also in other milling devices (e. g. PBM). Of course and in principle it is also possible to connect there a temperature sensor, but we do not. The reason is that – despite that the pressure may also give a hint about the internal temperature – there are different temperatures to be observed. This is the atmosphere temperature, which is not as important as the temperature of the grinding media (balls), and also the temperature during collision (several milliseconds) of the balls and the process temperature. The last we are able to measure as standard even if it is a hint only since it is influenced by the cooling water.
The vessel itself is cooled due to the energy input during High Kinetic Processing (HKP).

Processing under vacuum / leakage rate:

We indeed do not measure the leakage rate due to the simple reason that this is only a valid value after inspection and quality control res. before delivery. As soon as it is used the leakage rate would change.
Instead of that we test the grinding unit with overpressure (≥4bar according to a test procedure protocol). In some exceptional cases we test also the vacuum tightness of the grinding unit and the equipment, but this is not a standard procedure.
Please take into consideration that two different processes under vacuum are possible. Whereas during a static vacuum milling process the vacuum pump is connected and in operation (possible since there are adapters available and the flow rates are very low after preceding evacuation before starting the process) the vacuum-pump during a dynamic vacuum milling process is switched off (after the corresponding valves were closed). In the second case the leakage rage leads to a slight increase of the vacuum pressure during processing (depending on the condition of the grinding-unit).
Furthermore it should be mentioned here that vacuum pressure of course depends on the powder material as well. Humidity and small particle sizes normally needs to extend the preceding evacuation; maybe heating-up the system helps a bit as well. The application also should be checked on possible de-gassing of powder material or, if used, a PCA.

What about processing under elevated temperatures of standard grinding units?
In principle there are two ways for heating up the vessel. The recommended way is using a thermostat which is connected at the cooling circuit of the vessel. By this a temperature of approx. 90°C is possible – then (90°C) the software will stop the system since cooking water is not allowed in the cooling circuit (high pressure). Furthermore the grinding-unit is not equipped with heat isolation.
It is also possible to switch-off the cooling of grinding vessel; this is suitable for a test but there might some disadvantages in reproducibility. Short notes for both alternatives:
There is another cooling circuit for the bearing flange which in any case has to be connected and switched on.
Seals by Viton are used for the HTB-configuration (up to 150°C, standard grinding-unit) or the heated grinding unit W01-xlh (up to 200°C, special grinding-unit).

Return to top

General questions about Simoloyer®

Simoloyer® – some details, configurations, types

Maltoz®

Air-lock/inert-gas/vacuum

Simoloyer® – peripheral devices

Technical questions to Simoloyer®

Set-up/training/delivery conditions

Handling

Processing

Collection of further questions

Unsorted

General Questions about Simoloyer®

Simoloyer® – some details, configurations, types

Maltoz®

Air-lock/inert-gas/vacuum

Simoloyer® – peripheral devices

Technical questions to Simoloyer®

Set-up / training / delivery conditions

Handling

Processing

Collection of further questions

Unsorted

Some detailed questions and answers:

Cycle operation / discharging cycle

General questions about Simoloyer^®

Simoloyer^® – some details, configurations, types

Maltoz^®

Simoloyer^® – peripheral devices

Technical questions to Simoloyer^®

General Questions about Simoloyer^®

Simoloyer^® – some details, configurations, types

Maltoz^®

Simoloyer^® – peripheral devices

Technical questions to Simoloyer^®